In the prior art, it has been common for belt sanders to have a top mounted electric motor to drive a rear sanding belt drum through a timing belt. The sanding belt passes around the rear sanding belt drive drum and also around a front idler belt drum mounted on a supporting frame which may be retracted to permit changing of belts and adjusted to provide for proper tracking of the belt.
Such belt sanders having a top mounted electric motor are bulky and the center of gravity is substantially spatially removed from the sanding plane. Hence, said sanders are less stable than might be desirable in the operator's hands, and producing a flat, true surface with such machine requires substantial skill on the part of the operator.
It has been previously suggested to eliminate some of the balance problem by positioning the motor inside the path of travel of the sanding belt so as to thereby both decrease the overall height of the tool as well as to substantially lower the center of gravity.
In positioning the motor within the path of travel of the sanding belt, however, it is necessary that the electric wiring therefore, leading from the belt to the trigger switch, be well shielded from any possible contact with the edges of the sanding belt. Further, such positioning of the drive motor within the path of travel of the sanding belt reduces the amount of space available within the belt for belt tension spring means and tracking adjusting means.